1. Field of the Invention
The present invention relates generally to systems for producing apparent 3-dimensional images. More particularly, the present invention relates to systems for projecting images onto separate projection screens and then displaying the images in the form of planes of projection in such a manner as to provide audiences with a sensation of 3-dimensional viewing.
2. Description of Related Art
For many decades the motion picture and video display industries have attempted with various degrees of success to provide viewing systems which give a sensation of depth or 3-dimensional viewing to the audience. One early approach involved providing a greater visual depth for viewers of projections screens such as motion picture audiences. This approach consisted of increasing the width of the projection screen relative to its height and curving the projection screen. These screen modifications result in a viewing area which is very close to the normal human visual range and additionally creates increased depth illusion.
Another method is known as stereoscopic viewing and consists of simultaneously projecting images, photographed at different angles, onto a screen through polarizing filters which are oriented at right angles to each other. Viewers are required to wear a pair of special polarizing viewing spectacles which allows each eye to see only one image. The viewer's brain combines the images so that a resultant image having apparent 3-dimensional characteristics is observed.
Another system for creating 3-dimensional viewing is described in U.S. Pat. No. 2,952,182 and consists of projecting one image on a front screen and projecting a second image on a back screen which is located directly behind the front screen. In order for a viewer to observe the images projected on both screens, the front screen is formed of a wire mesh material which is painted with white pigment on the front, to maximize reflection, and painted black on the back to maximize absorption. The rear screen is a rear projection screen and allows light to pass through it so that it appears to originate from the screen. In order to avoid image "bleed" created by light from the front screen passing through the mesh and reflecting from the rear screen, a filter is positioned between the front and rear screens and at an angle to the front screen. This filter reflects about 80% of the light striking it while allowing sufficient light to pass through so that the viewer can observe the back screen. A real drawback associated with this system is the reduced visualization of the back screen caused by the presence of the filter. That is, only a small percentage of the light originating from the rear screen is transmitted to the viewer opposite the front screen, resulting in low intensity images.
None of the systems described above provides suitable apparent 3-dimensional viewing without stereoscopic glasses. Furthermore, none of these prior art systems provide relatively small screens and audience sizes of less than about 50 individuals. For example, display booths which utilize video projection equipment and screens to advertise, provide public information, or promote services are restricted to conventional small screen viewing systems without the enhanced effect of 3-dimensional images.
Accordingly, it is an object of the present invention to provide a system for 3-dimensional viewing which does not require viewers to wear stereoscopic viewing spectacles.
It is also an object of the present invention to provide a system for 3-dimensional viewing without image "bleed".
It is further an object of the present invention to provide a system for 3-dimensional viewing configured for display booths or kiosks designed for small screens and limited audience sizes.
It is another object of the present invention to provide a system for 3-dimensional viewing which can be constructed economically.